UTM link checker

Before you share a tagged link, check that its campaign parameters sit in the query, that every escape in it is valid and that its values match the rest of the campaign. Google's campaign URL guidance says to always use utm_source, utm_medium and utm_campaign, and utm_source=google is a different source from utm_source=Google. Paste your links into the checker above to see which of these each one gets wrong.

RFC 3986, section 3.4 defines the query as starting at the first ? and ending at a # or the end of the link. Section 3.5 starts the fragment at the # and runs it to the end of the link. So a utm_source written after the #, as in example.com/guide#pricing?utm_source=newsletter, is part of the fragment, not the query. Put the campaign parameters before the #: example.com/guide?utm_source=newsletter#pricing.

A percent sign starts an escape. RFC 3986, section 2.1 defines a percent-encoded octet as a % followed by two hexadecimal digits. %20 follows that shape; %zz, or a % at the end of a value, does not. Rebuild a value like that from the original campaign name rather than guessing what it meant.

Google's campaign URL guidance treats parameter values as case sensitive, so Facebook and facebook are reported as two separate sources. Google also recommends using lowercase as the standard.

Missing parameters show up as (not set) in reporting, so a link without utm_source, utm_medium or utm_campaign leaves a gap in the campaign reports.

The %20 in a value such as spring%20sale is a valid percent-encoded octet, not a broken escape. Choose either hyphens or spaces for a campaign name and use the same form on every link.

In GA4, channels are rule-based definitions of your traffic sources. Paid Search, for example, is the channel by which users arrive via ads on search-engine sites, and Organic Social the channel by which they arrive via non-ad links on social sites. Channel definitions are not case sensitive and cannot be edited. The parameter values themselves are case sensitive, so Email and email still appear as two medium values in reports.

Unassigned is the value Analytics uses when no other channel rule matches the event data. The definitions reflect Google's current view of each channel and may evolve as the market changes, so treat the channel shown for each link as an estimate from the rules as published, and re-check it when a report looks wrong. Read the GA4 channel guide next, then the source vs medium guide.